The present invention relates generally to an appliance timer, and more particularly to an apparatus and method for securing a control knob to a control shaft an appliance timer.
Appliance timers are commonly used in many household appliances, such as dishwashers, clothes washers, and clothes dryers. The appliance timer controls operation of the appliance by actuating and deactuating a number of switch assemblies which start and stop various work functions within the appliance such as a rinse function in the case of a clothes washer. The switch assemblies within the appliance timer are actuated and deactuated as a result of interaction between a number of a cam surfaces defined in a camstack of the appliance timer and a number of cam followers which are respectively associated with the switch assemblies. The camstack may be manually positioned to actuate and deactuate the switch assemblies associated with a particularly desired work function by rotating a control knob, which is typically located on the front of the appliance.
A control shaft couples the control knob to the camstack such that the camstack may be rotated in a direction corresponding to the rotation of the control knob by a user. As such, a locking mechanism is typically utilized to lock or otherwise secure the control knob to the control shaft.
One such locking mechanism for securing the control knob to the control shaft includes a locking pin which is friction fit into an axial bore defined in the control shaft. The locking pin forces the tips of the control shaft outwardly against the sides of a recess defined in the control knob. The force applied by the tips of the control shaft against the control knob effectively secure the control knob to the control shaft.
Such a design has a number of drawbacks associated therewith. For example, difficulties may arise during the assembly of an appliance timer which includes such a locking mechanism. In particular, due to manufacturing variations, the geometry of the locking pin may deviate from its intended design thereby rendering the locking pin difficult to install. Moreover, the force necessary to insert the locking pin into the control shaft may vary due to such a variation of the geometry of the locking pin thereby potentially preventing the locking pin from being fully xe2x80x9cseatingxe2x80x9d in the control shaft. In either case, the control knob may not be properly secured to the control shaft thereby necessitating rework or repair during the manufacturing process.
What is needed therefore is an apparatus and method for securing a control knob to a control shaft which overcomes one or more of the aforementioned drawbacks. What is further needed is an apparatus and method for securing a control knob to a control shaft which allows for the reliable attachment of the knob to the shaft irrespective of typical manufacturing variations.
In accordance with one embodiment of the present invention, there is provided a control shaft and knob assembly. The assembly includes a control knob having a slot defined therein. The assembly also includes a control shaft which (i) has a bore extending therethrough, (ii) includes a spring arm which is positionable within the slot of the control knob, and (iii) has an opening defined therein. The assembly further includes a locking pin having a first retention member secured thereto. The locking pin is positionable in the bore of the control shaft. When the locking pin is positioned in the bore of the control shaft (i) the locking pin is positioned to inhibit inward deflection of the spring arm, and (ii) the first retention member is received into the opening of the control shaft.
In accordance with another embodiment of the present invention, there is provided a control shaft and knob assembly. The assembly includes a control knob having a slot defined therein. The assembly also includes a control shaft which (i) has a bore extending therethrough, (ii) includes a spring arm which is positionable within the slot of the control knob, and (iii) has a recess defined therein. The assembly further includes a locking pin having a first retention member secured thereto. The locking pin is positionable in the bore of the control shaft. When the locking pin is positioned in the bore of the control shaft (i) the locking pin is positioned to inhibit inward deflection of the spring arm, and (ii) the retention member is received into the recess of the control shaft.
In accordance with yet another embodiment of the present invention, there is provided a method of securing a control knob to a control shaft. The method includes the step of advancing a spring arm of the control shaft into a slot of the control knob. The method also includes the step of advancing a locking pin through a bore defined in the control shaft until (i) an end portion of the locking pin extends out of the bore and is located at a position in which the end portion of the locking pin inhibits inward deflection of the spring arm, and (ii) a first retention member which is secured to the locking pin extends into an opening defined in the control shaft.
It is therefore an object of the present invention to provide a new and useful apparatus for securing a control knob to a control shaft of an appliance timer.
It is a further object of the present invention to provide an improved apparatus for securing a control knob to a control shaft of an appliance timer.
It is moreover an object of the present invention to provide a new and useful method of securing a control knob to a control shaft of an appliance timer.
It is yet further an object of the present invention to provide an improved method of securing a control knob to a control shaft of an appliance timer.
It is moreover an object of the present invention to provide an apparatus for securing a control knob to a control shaft of an appliance timer that provides for ease of manufacture relative to heretofore designed appliance timers.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and the attached drawings.